Pumps



E. CHANTON Feb. 8, 1966 PUMPS 2 Sheets-Sheet 2 Filed Dec. 23, 1963TTORNEYS United States Patent 3,233,553 PUMPS Edmond Qhanton,LHay-les-Roses, France, assignor to Societe Generale de Mecanique et deMctailurgie, Seine, France, a society of France Filed Dec. 23, 1963,Ser. No. 332,518 Claims priority, appiication France, Dec. 28, 1962,

20,121 6 Claims. (Cl. FAB-449) The present invention relates to pumpsfor a fluid either liquid or gaseous.

The invention relates to a pump comprising the following elements: abody having a cylindrical inner surface the respective axial ends ofwhich are connected respectively to a suction orifice and to a deliveryorifice, a shaft the middle line of which is of helical shape housed insaid body, the length of this shaft being equal to at least one pitch ofthe helix, the cross section of this shaft being constant along itslength and having the same total width 1 in all directions, the two endsof said shaft being joined to journals disposed along the axis of saidhelix; a plurality of identical transverse plates provided in theircentral portions with apertures having two rigid edges parallel to eachother and perpendicular to a direction D, the distance between saidedges being equal to I, said plates having their central aperturesmounted on said shaft and being juxtaposed to one another; a flexibleand fluidtight tubular sheath surrounding the juxtaposition of platesand forming therewith a deformable element fitting with a sliding fit inthe body, the mean line of this element being sinuous but plane andevery cross Section thereof differing from the inner cross section ofthe body in which it is located only by a rectangle two sides of whichare parallel to direction D and have a length 0 and the two other sidesof which are equal to the greatest dimension of said cross sections in adirection perpendicular to D; and means for rotating said shaft whichimpart to every plate a rectilinear reciprocating movement of anamplitude 0, parallel to D, thus creating between the external surfaceof the sheath and the inner surface of the body closed spaces movinglongitudinally from one end of the body to the other and which serve toconvey the fluid.

The present invention consists in giving said plates a circular externaloutline and in providing each of them in eccentric position with atleast one slot elongated in direction D, through which passes, with someplay in said direction D but without play in the direction perpendicularto D, a rectilinear guiding rod rigid with the body and extendingparallelly to the generatrices thereof.

The function of the guiding rods is to prevent the plates from rotatingabout their centers when the helicoidal driving shaft rotates.

Therefore it is the presence of these rods which permits of making useof plates of circular outline, a shape which has great advantagesconcerning the manufacture of these plates and chiefly that of thesheath in which they are located. Said sheath may then consist of a meretubular element of revolution about its axis. Furthermore as thetendency of the plates to rotate about their center is prevented by saidrods, the sheath undergoes no torsional stresses, which is advantageousto preserve it in good state. Another advantage is that, on the onehand, due to this elimination of torsional stresses applied to thesheath and, on the other hand, due to the shape of revolution thereof,it is possible and easy to constitute it of two superposed envelopes,the external one resisting to the fluid to be pumped and the internalone resisting to the lubricant provided for the bearings and the plates.

3 ,233,553 Patented F eh. 8, 1966 Preferred embodiments of the presentinvention will be hereinafter described with reference to the appendeddrawings, in which:

FIG. 1 is a longitudinal section on the line II of FIG. 2 of a pump madeaccording to the present invention;

FIG. 2 is a longitudinal section on the line II-II of FIG. 1;

FIG. 3 is a part cross section on the line HIII1 of FIG. 1;

FIG. 4 shows, similarly to FIG. 3, the same pump for another angularposition of its driving element;

FIG. 5 is a longitudinal sectional view on the line V-V of FIG. 6 of apreferred embodiment of the pump according to the present invention;

FIG. 6 is a transverse section-a1 view on the line VI-Vl of FIG. 5;

FIG. 7 is a cross section of a shaft adapted to be used in pumpsaccording to the present invention.

It is already known to make pumps in the following manner.

Closed spaces are created between the inner rigid cylindrical surface ofa hollow pump body and the undulated external surface of a deformableelement having a flat sinuous middle line, disposed inside said body andthese spaces are moved longitudinally from one end to the other of thewhole.

In order to create said spaces, the two above mentioned surfaces arechosen in such manner as to be tangent to each other along, on the onehand, the crests of the undulations of the undulated surface and, on theother hand, at least one flat sinuous line in each of the two planes,parallel to said middle line, tangent to said two surfaces.

In order to move said spaces, the working portion of the deformableelement is arranged in such rnanner that each of its transverse sectionscan undergo, without deformation, translatory rectilinear reciprocatingsliding movements in a direction D, independently of the adjacent crosssections of said element, said slid-ing movements being guided by twoopposed flat bearing surfaces of the body in which the deformableelement is fitted, every cross section being designed in such manner asto apply in a fluidtight manner, at every end of its stroke, against thecorresponding portion of said rigid surface, one of the two portions ofits periphery which are joined to each other along said flat bearingsurfaces, and the transverse sliding displacement of every cross sectionare controlled in such manner that each of them is slightly offsettransversely with respect to the adjacent ones, and that thejuxtaposition of these cross sections has an undulated or sinuoussurface.

For this purpose every cross section of the deformable element isprovided with an aperture including two rigid bearing elements facingeach other (considered in direction D), a shaft of helical orsubstantially helical mean line being engaged in said apertures so thatevery cross section of said shaft is permanently tangent to the tworigid bearing sides of the corresponding aperture,

and said shaft is rotated.

In order to constitute the deformable sinuous element it has alreadybeen proposed to make use of a juxtaposition of plates enveloped by aflexible and fluidtight sheath, but to prevent said plates from movingangularly under the influence of the rotation of the central helicalshaft, which displacements would cause said shaft to be blocked, saidplates (and therefore the inner surface of the cylindrical body) weregiven a rectangular transverse perimeter. This involves seriousdifficulties concerning, on the one hand, the manufacture and theguiding of the sheath and, on the other hand, the life of said sheathwhich is constantly subjected to torsional stresses to transmit to thebody the torsional forces applied to the plates.

These drawbacks are avoided according to the present invention by givingthe plates a circular outline and preventing rotation of said plates bymeans of longitudinal rods rigid with the body.

In the embodiment of FIGS. 1 to 4, the rigid pump body comprises ahollow cylinder 1 the inner cross section of which is in the form of twohalf circles (FIG. 3) of diameter a joined together by two straight lineportions parallel to direction D and of a length 0. This cylinder 1 isconnected at its ends, respectively with two chambers 2 and 3 incommunication with connections 4 and 5 for the suction and deliverypipes.

The deformable element having an undulated surface consists of thejuxtaposition of thin plates 6 of circular outline (the thickness ofsaid plates being for instance 1 mm.). The element constituted by thewhole of said plates is fitted in a flexible and fluidtight sheath 7 theouter diameter of which is equal to a.

Each of the plates 6 is provided in its central portion with arectangular aperture 3 the small sides of which are parallel to D. Eachof the plates further comprises two slots 9 parallel to D and disposedsymmetrically to each other with respect to aperture 8.

A shaft 1% extends transversely to said plates 6, through the aperture 8thereof. The cross section of this shaft is a circle the diameter ofwhich is equal to the length l of the small sides of every rectangularaperture 3. The mean line of this shaft, or to be more accurate, of theworking portion of this shaft, is a portion of a helix hav ing adiameter equal to c and a pitch equal to p. The length of this shaftportion is at least equal to p. The ends of said helical portion of theshaft may be gradually joined to the axis of the helix, as shown by FIG.1, which permits, on the one hand, of keeping stationary the plates 6corresponding to said ends of the shaft, when this shaft is rotated,and, on the other hand, of joining without discontinuity said shaft tojournals 11 coaxial with the helix and mounted in bearings 12, with theinterposition of ball bearings 13. Thus sheath 7 may be fixed on theouter cylindrical surfaces 16 rigid with bearing surfaces 12, by meansof annular fixation means 14.

Through the slots 9 of plates 6 extend cylindrical rods 16 the crosssection of which is a circle having a diameter equal to the width ofsaid slots. These rods 15 are fixed at both ends to the pump body andthey guide the transverse displacements of plates 6 while preventing anyrotation thereof when shaft is rotated.

At any time, deformable structure 67 has a sinuous shape and the meanline thereof is flat and sinuous with an amplitude of 0/2. The systemconsisting of the whole of plates 6 and sheath 7 in which they aremounted remains tangent to the two flat surface portions of easing 1which are parallel to slots 9 (and which are horizontal and designatedby reference numeral 17 in FIGS. 1 and 3), and the crests 19 of the wavystructure 6-7 are tangent to the curved surfaces of cylinder 1 (FIGS. 2and 4). Thus closed spaces 18 of a volume equal to /2 a.c.p. are createdbetween sheath 7 and cylinder 1.

It suflices to rotate shaft to, for instance manually or by eans of anengine, to cause each of these spaces to travel from the upstream to thedownstream end of the whole. As a matter of fact, every plat-e 6undergoes a rectilinear horizontal movement of amplitude 0.

FIGS. 3 and 4 show the respective positions occupied by a plate 6 fortwo angular positions of shaft 10 at 90 to each other.

It is noted that since the length of the active portion of the device isat least equal to one pitch of the helix every space 18 is separatedfrom the upstream chamber 2 before being placed .in communication withthe downstream chamber 3. Therefore fluidtightness is ensured betweenthese chambers, so that packing joints are unnecessary.

Furthermore, due to the fact of the fluidtight connection between sheath7 and outer surfaces 16 the circuit for the fluid that is pumped iswithout communication with the inside of said sheath. It is thereforepossible to feed a lubricant to the inside of this sheath for instancein order to reduce wear and tear due to the transverse sliding movementsof plates 6 against one another and also to lubrify bearings 12. Conduit39 (PEG. 1) has been pro vided for this purpose.

The pump works for both directions of rotation of shaft When thedirection of rotation of the shaft is reversed the direction of flow ofthe fluid is also reversed.

The portions of plates 6 which are most subjected to wear and tear areadvantageously reinforced. This is the case of reinforcement 25Bextending along the longer sides of apertures 8 (FIGS. 3 and 4 Each ofthese reinforcements may either be fixed on every plate 6 individuallyor consist of a flexible plate corresponding to the whole of said plates6 and interposed between said apertures and the shaft.

The preferred embodiment of the invention illustrated by FIGS. 5 and 6includes the elements designated by reference numerals 1 to 13 inclusiveand also guiding rods 15 and spaces 13. It further includes thefollowing features.

In order to reduce the wear between guiding rods 1:? and the edges ofslots 9, the contacting surfaces of these elements are increased byproviding rods 15 with two flat bearing surfaces 15 parallel todirection D. These fiat portions may be connected together by curvedsurfaces or they may consist of the faces of a drawn element having arectangular or square cross section.

in order to reduce the wear by friction between every plate and theadjacent ones and also between every plate and shaft 19 and rods 15, theplates are made of a material having a very good coefiicient offriction, in particular of a phenol resin reinforced with cotton andloaded with colloidal graphite, such as known under the trademark nameof Celoron.

In order further to reduce the wear by friction between the plates, itis advantageous to provide them with a multiplicity of holes 41. Thishas the further advantage of improving lubrication and reducing theweight of the whole.

In order to improve the lubrification of the plates, it is advisable tocool down the oil 42 used for this purpose, which may easily reach atemperature of 5()-6 This cooling is obtained by circulating said oil ina closed circuit including an external portion 43 provided with coolingfins 44, said circuit being of course separated in a fluidtight mannerfrom the circuit of the fluid that is pumped.

In order to facilitate the mounting of sheath 7 about the plurality ofplates 6, this sheath is made in the form of a moulded resilient bagincluding a central portion in the form of a tube of revolution, and twoend portions, each in the form of a frusturn of a cone. One of said endportions is convergent toward the end of said portion whereas, on thecontrary, the other end portion is divergent. The initial diameter ofthe tubular portion is smaller than the diameter of plate a so that,when said plates are introduced into the bag, they stretch itresiliently, thus eliminating any risk of play.

The fitting of the bag is advantageously performed in the followingmanner:

Rods and shaft 1d are first mounted in one of the bearings 12. Thenplates 6 are stacked on these elements and the other bearing 12 issecured. The composite structure thus formed is inserted into bag 7though the flaring end tiereof, whereby said bag is expended. At the endof this operation, the two end portions (each in the form of a frustumof a cone) are elastically applied against corresponding frusto-conicalseats complementary of the respective bearings 12. In order to ensureperfect fluidtightness, the annular edges forming the ends of bag '7(one 7 on the right and the other 7 on the left) are applied againstcorresponding surfaces or bearings 12, for instance by screwing ofexternal rods 45 secured to the axial ends of the pump body.

In a preferred embodiment of this pump body, every chamber 2 or 3 ismoulded integral with the corresponding connection 4 or 5 and forms anindependent piece which is axially applied against hollow cylinder 1through the above mentioned rods 45, with the interposition of toroidalpacking joints 46.

Merely by way of indication some dimensions of the elements of theconstruction illustrated by FIGS. 5 and 6 will now be given:

Sheath 7: 4 mm. thick, this sheath consisting of two layers superimposedon each other, one on the inside being relatively thick and made of anelastomer capable of resisting the action of the lubricating oils thatare used and the other on the outside, thinner, inert with respect tothe liquid that is pumped and consisting for instance ofchlorosulfonated polyethylene known under the trademark name of Hypalonwhich substance might be replaced by the copolymer of fluorovinylideneand hexafluoropropylene designated by the trademark name of Viton, bypolytrifluoromonochloroethylene or even by polytetrafluoroethylene,which is sufilciently resilient under the small thickness that isconsidered:

Inner diameter of the tubular portion of sheath 7: 62 min. beforemounting and 65 mm. after mounting;

Plates 6: made of the reinforced phenol resin designated by thetrademark name of Celoron having a thickness of 1 mm. and a diameter of75 mm.;

Number of plates: 25 0;

Shaft made of nitrided steel having a diameter of 30 mm. and a usefullength of 250 mm. (only 200 mm. of which correspond to a true helix, theremainder corresponding to the portions where said shaft is joined tothe journals);

Pitch of the helix: 100 mm., for a diameter of said helix equal to 6mm.;

Number of revolutions per minute of the shaft: 900;

Theoretical output: 2,700 liters per hour;

Practical output when the delivery pressure is zero: 2,700 liters perhour;

Practical output with a substantial delivery pressure: 2,300 l./h.

If use were made of a shaft 10 of the same diameter as the preceding onebut corresponding to a helix having a diameter of 8 mm. and a pitch of200 mm., the theoretical output would be 7,200 l./h.

Of course there may be modifications of the specific construction abovedescribed.

In particular the cross section of the helical shaft, while remainingconstant along this shaft and having the same total Width in alldimensions, might be noncircular; for instance it might have the shapeof the Trezel eccentric cam shown at 4-7 in FIG. 7 the outline of thiscam may be easily constructed by means of circular arcs from anequilateral triangle ABC having one of its apexes on the rotation shaft.

The number of pitches of the active portion of the shaft might begreater than 1 or 2, every shaft corresponding to a pumping stage.

If the fluid that is pumped is compressible the pitch of the helix wouldbe variable along the shaft.

Of course the inner cylindrical surface of the pump body, instead ofbeing integral with this body, might consist of a lining secured in saidbody.

Said surface, instead of being hard, might be semir-igid, for instancemade of hard rubber so as to improve fluidtightness of the spaces thatare formed.

In a general manner, while the above description discloses what aredeemed to be practical and efficient embodiments of the presentinvention, said invention is not limited thereto as there might bechanges made in the arrangement, disposition and form. of the partswithout departing from the principle of the invention as comprehendedwithin the scope of the appended claims.

What I claim is:

1. A pump which comprises, in combination, a pump body provided with acavity having a cylindrical inner surface and respective suction anddelivery orifices provided at the ends of said pump body respectively,said inner surface consisting of two half circular cylindrical portionsof the same diameter disposed opposite each other, with theirconcavities turned touvard each other and joined together by twoparallel flat portions, a shaft having its mean line in the form of ahelix disposed in said body coaxially therewith, to length of this shaftbeing at least equal to the pitch of said helix, the cross section ofthis shaft being the same over the length of said shaft and having thesame width in all directions, said shaft including, at its respectiveends, cylindrical trunnions journalled in said body coaxially therewith,a multiplicity of adjacent plates transverse to the axis of said helix,each of said plates being provided with a central aperture having twolonger sides parallel to each other and perpendicular to the directionof the flat portions of the pump body inner surface, said two sidesbeing at a distance from each other equal to the above mentioned widthof the cross sections of said shaft, all of said plates having theirapertures engaged on said shaft, the outline of each of said platesbeing circular, each of said plates being provided with at least oneslot parallel to said last mentioned direction, all of said slots havingthe same .width, at least one rod carried by said body in fixedpositione and fitting slidably in said slots, and a fiuidtight flexibletubular sheath surrounding all of said plates so as to form therewith adeformable structure housed in said cavity with a sliding fit, the endsof said sheath being secured in a fluidtight maner respectively to thesuction orifice and to the delivery orifice of said pump body.

2. A pump according to claim 1 wherein the guiding rod has two flatsurfaces parallel to said direction, against which surfaces the edges ofsaid slots parallel to said direction are slidable.

3. A pump according to claim 1 wherein the tubular sheath comprises twolayers superimposed on each other, that intended to come into contactwith the fluid to be pumped being made of a material especiallyresistant with respect to this fluid.

4. A pump according to claim 1 wherein the plates are provided with amultiplicity of holes.

5. A pump according to claim 1 wherein said sheath is in the form of amoulded resilient b ag stretched by the plates packed therein one end ofsaid bag flaring out whereas the other one is slightly retracted.

6. A pump according to claim 1 wherein the mean line of the shaft is avariable pitch helix.

References (Jited by the Examiner UNITED STATES PATENTS 2,752,860 7/1956Waldin 103-149 FOREIGN PATENTS 637,586 6/ 1939 Germany.

MARK NEWMAN, Primary Examiner.

WARREN E. COLEMAN, Assistant Examiner.

1. A PUMP WHICH COMPRISES, IN COMBINATION, A PUMP BODY PROVIDED WITH ACAVITY HAVING A CYLINDRICAL INNER SURFACE AND RESPECTIVE SUCTION ANDDELIVERY ORIFICES PROVIDED AT THE ENDS OF SAID PUMP BODY RESPECTIVELY,SAID INNER SURFACE CONSISTING OF TWO HALF CIRCULAR CYLINDRICAL PORTIONSOF THE SAME DIAMETER DISPOSED OPPOSITE EACH OTHER, WITH THEIRCONCAVITIES TURNED TOWARD EACH OTHER AND JOINED TOGETHER BY TWO PARALLELFLAT PORTIONS, A SHAFT HAVING ITS MEAN LINE IN THE FORM OF A HELIXDISPOSED IN SAID BODY COAXIALLY THEREWITH, THE LENGTH OF THIS SHAFTBEING AT LEAST EQUAL TO THE PITCH OF SAID HELIX, THE CROSS SECTION OFTHIS SHAFT BEING THE SAME OVER THE LENGTH OF SAID SHAFT AND HAVING THESAME WIDTH IN ALL DIRECTIONS, SAID SHAFT INCLUDING, AT ITS RESPECTIVEENDS, CYLINDRICAL TRUNNIONS JOURNALLED IN SAID BODY COAXIALLY THEREWITH,A MULTIPLICITY OF ADJACENT PLATES TRANSVERSE TO THE AXIS OF MULTIPLICITYOF ADJACENT PLATES TRANSVERSE TO THE AXIS OF CENTRAL APERTURE HAVING TWOLONGER SIDES PARALLEL TO EACH OTHER AND PERPENDICULAR TO THE DIRECTIONOF THE FLAT PORTIONS OF THE PUMP BODY INNER SURFACE, SAID TWO SIDESBEING AT A DISTANCE FROM EACH OTHER EQUAL TO THE ABOVE MENTIONED WIDTHOF THE CROSS SECTIONS OF SAID SHAFT, ALL OF SAID PLATES HAVING THEIRAPERTURES ENGAGED ON SAID SHAFT, THE OUTLINE OF EACH OF SAID PLATESBEING CIRCULAR, EACH OF SIAD PLATES BEING PROVIDED WITH AT LEAST ONESLOT PARALLEL TO SAID LAST MENTIONED DIRECTION, ALL OF SAID SLOTS HAVINGTHE SAME WIDTH, AT LEAST ONE ROD CARRIED BY SAID BODY IN FIXED POSITIONEAND FITTING SLIDABLY IN SAID SLOTS, AND A FLUDTIGHT FLEXIBLE TUBULARSHEATH SURROUNDING ALL OF SAID PLATES SO AS TO FORM THEREWITH ADEFORMABLE STRUCTURE HOUSED IN SAID CAVITY WITH A SLIDING FIT, THE ENDSOF SAID SHEATH BEING SECURED IN A FLUDTIGHT MANER RESPECTIVELY TO THESUCTION ORIFICE AND TO THE DELIVERY ORIFICE OF SAID PUMP BODY.